NASA’s sturdy little Mars rover, Curiosity, has discovered more signs that liquid water was present in the ancient Martian environment. Using instruments on its robotic arm, Curiosity inspected rocks Thursday (Sept. 19) at one of five planned waypoints on its journey along Gale Crater toward the massive, almost three-and-a-half-mile high Mount Sharp.
“We examined pebbly sandstone deposited by water flowing over the surface, and veins or fractures in the rock,” said Curiosity science team member Dawn Sumner in a statement released by NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. “We know the veins are younger than the sandstone because they cut through it, but they appear to be filled with grains like the sandstone.” Sumner, of the University of California-Davis, had a leadership role in planning the scientific pitstop.
The science team managing Curiosity planned the stop-overs in order to collect information about Martian geology en route between the “Glenelg” area of Gale Crater, where the rover worked for the first half of 2013, and Mount Sharp. Drilled samples from “Yellowknife Bay” rocks in the Glenelg area revealed a watery primordial environment with conditions favorable for the existence of microbial life. For NASA, that meant Curiosity had achieved its primary scientific goal.
According to Sumner, scientists want to understand the history of water in Gale Crater and find answers to such questions as whether the flow of water that deposited the pebbly sandstone at Waypoint 1 occurred at approximately the same time as the water flow at Yellowknife Bay.
“If the same fluid flow produced the veins here and the veins at Yellowknife Bay, you would expect the veins to have the same composition,” Sumner explained, adding, “We see that the veins are different, so we know the history is complicated. We use these observations to piece together the long-term history.”
The Waypoint 1 site, located at a rock outcrop dubbed “Darwin,” was originally picked on the basis of images taken by NASA’s Mars Reconnaissance Orbiter showing the presence of conglomerate rock. According to JPL, finding the veins was “a bonus.”
Curiosity spent a total of four days investigating two spots at the Darwin outcropping, using two instruments mounted in the turret at the end of its robotic arm: the Alpha Particle X-ray Spectrometer used for identifying chemical elements and the Mars Hand Lens Imager, which reveals a target’s shapes, textures, and colors.
Curiosity landed inside the Red Planet’s Gale Crater in August, 2012, and embarked in July on its 5.3 mile (8.6 kilometer) journey to Mount Sharp, which has always been the rover’s primary destination. While the more than 450-member science team is impatient to reach the mountain, they were willing delay Curiosity’s arrival there in the interest of examining rocks along the way, said Curiosity team member Kenneth Williford.
Once the Martian dune-buggy rolls onto the many-layered slopes of Mount Sharp, it will search for clues about how the Martian environment has changed over time.